Sensor element for capacitive differential-pressure sensing

US7992443B2 · kind B2 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Bernhard Opitz · Leonberg, DE
• Christian Doering · Stuttgart, DE
• Hans Artmann · Magstadt, DE
• Janpeter Wolff · Gerlingen, DE
• Remigius Niekrawietz · Stuttgart, DE

Key dates

• Filing date: Dec 22, 2009
• Grant date: Aug 9, 2011
• Expiry date: Feb 3, 2030

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B81B2201/0264
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A sensor design, respectively a micromechanical sensor structure for capacitive relative-pressure measurement, that will allow very small pressure differentials to be reliably recorded at high absolute pressures even in harsh, particle-laden measuring environments. For that purpose, the micromechanical sensor element includes a deflectable diaphragm structure which is provided with at least one deflectable electrode, and a fixed support structure for at least one fixed counter-electrode which is located opposite the deflectable electrode. The diaphragm structure includes two mutually parallel configured diaphragms that are joined rigidly to one another via at least one connecting crosspiece, so that each application of force to one of the two diaphragms is directly transmitted to the respective other diaphragm. The first diaphragm is able to be pressurized by a first measuring pressure emanating from the front side of the sensor element, and the second diaphragm is able to be pressurized by a second measuring pressure emanating from the rear side of the sensor element. The fixed counter-electrode is located in the sealed volume between the two diaphragms of the diaphragm structure.